Hebrews 6:1-6 is often times taken out of context and misinterpreted. Very few verses can be correctly interpreted, or applied, without reading the entire context. Cults and other false doctrines are a result of taking Scripture out of context and, instead of taking the meaning from the Scriptures (exegesis), inserting meaning into them (eisegesis).
In Hebrews 6:1-6, the author (most believe to be Paul the Apostle) is speaking to true Christians who have been saved (past tense) and HAVE the “full assurance of hope unto the end” (verses 11 and 19). Yet, some professing believers were reverting back to the old covenant (which the Lord Jesus Christ has already fulfilled) instead of moving forward in Grace and maturing as Christians, becoming useful to the Lord.
If the Lord Jesus Christ did not come and die as our substitute, then the law would only condemn. No descendant of Adam has ever been justified by the law (Romans 3:19-20). They were always justified by Faith in the Substitutes of the Old Testament. Even those sacrifices did not take away sin, but stood as a clear reminder of the complete necessity of the One and Only Sacrifice that COULD and DID take away ALL sin of those who would trust in Him … the coming Messiah… the Lord Jesus Christ.
So the author of Hebrews, here (Hebrews 6:6), is using an impossibility to make a very clear statement. That if the ultimate sacrifice of the Lord Jesus Christ was not enough, then there is no hope at all. OF COURSE Jesus Christ is eternally sufficient to fully justify all who repent and believe the Gospel (Mark 1:15). These agree with God that they are worthless sinners and so come to the foot of the Cross and trust in His Finished work at Calvary.
He is saying that if a saved person (a messianic Jew in this case) goes back to the old covenant, taking up the law, he is rejecting Christ. If that were to happen, there would be no hope at all because he would be going right back to the law that Christ satisfied. Thhis would be like crucifying Him all over again and putting Him to open shame.
If I may paraphrase, he is saying “You have been saved by the Blood of Jesus Christ! Why are you going back to the law that He satisfied for you? Leave the law behind you, because it has no effect on you … you have been justified already. Going back to the law is saying “The Lord Jesus Christ is not enough.” You are saved … He died for YOU. He fulfilled the law for YOU. He justified YOU. And now I am having to explain to you the very basics of the Gospel that I would normally need to explain only to newly saved individuals. I should be ministering to you with much more mature truths, but you still need the basics.”
What these early Christians were doing could be compared to your father paying off your mortgage, out of the kindness of his heart, just because he loves you. Then you continue to pay payments because you don’t believe the lender will accept his money because it didn’t come from you. You believe that the bank requires something from YOU. However, the bank teller, like Paul, would likely tell you, “The debt has been paid. Why are you trying to pay for something that has already been paid? Your father paid it in full and you no longer owe us anything. The home belongs to you now. So go live in it.”
But in the case of these Messianic Jews, they were taking it a step further. Not only were they putting Christ to shame by saying He was not enough (through their actions), these actions also showed that they believed THEY could do something themselves (out of their own resources).
The reality is that we have absolutely no hope whatsoever without the Lord Jesus Christ. It is all about Him. We are nothing. He is everything.
They did not understand that. Although they were saved, they likely lived miserable lives with no peace before the writer of Hebrews corrected them and reminded them that they were nothing and that Christ was and is everything.